Field of the Invention
The present invention relates to an aluminum composite twisted wire conductor, an aluminum composite twisted wire, and a wire harness.
Description of Related Art
In the related art, a plurality of copper strands are first-twisted to form an assembled twisted wire, and then the plurality of assembled twisted wires are secondly twisted to form a composite twisted wire conductor. In such a composite twisted wire conductor, the assembled twisted wires are stacked from the center. In the composite twisted wire conductor, a second twisting direction in each layer is set to be opposite to a second twisting direction of the adjacent layer in order to keep the outer diameter of the conductor to be more circular shape. However, in a case where the above configuration is employed to strands made of aluminum or an aluminum alloy which is degraded compared to copper in strength and elongation, the strands in the adjacent layers come into point contact with each other since the second twisting directions are opposite. Therefore, the strands may be easily disconnected, and a requirement for bending resistance comes to be unsatisfied.
There is disclosed a composite twisted wire conductor in which the first twisting and the second twisting both are set to be in the same direction (see, for example, the patent document 1: JP-A-2006-156346). In the composite twisting conductor, since the first twisting and the second twisting both are set to be in the same direction, the bending resistance can be improved. In other words, the strands of the assembled twisted wire come into surface contact with each other even between the adjacent layers, and the strands are hardly disconnected, so that the bending resistance is improved.
[Patent Literature 1] JP-A-2006-156346
According to a related art, in a composite twisted wire conductor, a bending resistance can be improved, but a strand of an assembled twisted wire of an outer layer easily enters between strands of the assembled twisted wire of an inner layer, and a shape of a composite twisted wire conductor is easily deformed due to a relation that a twisting directions are unified to the same direction. In a case where the shape is deformed, it leads to a deviation of a coating thickness, and also leads to a degradation in peeling workability.